• Prostate-specific antigen failure by American Society for Therapeutic Radiology and Oncology (ASTRO) definition [ Designated as safety issue: No ]
• Disease specific survival as assessed by failure (a competing risk cause of death not necessarily due to disease specific cause) [ Designated as safety issue: No ]
• Local progression as measured by clinical criteria and histologic criteria by biopsy [ Designated as safety issue: No ]
• Distant metastases by clinical or bone scan [ Designated as safety issue: No ]
• Genitourinary and/or gastrointestinal toxicity ≥ grade 2 by RTOG toxicity criteria [ Designated as safety issue: Yes ]
• Erectile Function by International Index of Erectile Function (IIEF) [ Designated as safety issue: No ]
• Global Quality of Life (QOL) by Spitzer QOL Index (SQLI) [ Designated as safety issue: No ]
• Quality adjusted survival by SQLI [ Designated as safety issue: No ]

• Prostate-specific antigen failure by American Society for Therapeutic Radiology and Oncology (ASTRO) definition at 5 years
• Disease specific survival as assessed by failure (a competing risk cause of death not necessarily due to disease specific cause) at 5 years
• Local progression as measured by clinical criteria and histologic criteria by biopsy at 5 years
• Distant metastases by clinical or bone scan at 5 years
• Genitourinary and/or gastrointestinal toxicity ≥ grade 2 by RTOG toxicity criteria at 5 years
• Erectile Function by International Index of Erectile Function (IIEF) at 5 years
• Global Quality of Life (QOL) by Spitzer QOL Index (SQLI) at 5 years
• Quality adjusted survival by SQLI at 5 years

RATIONALE: Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. It is not yet known which dose of radiation therapy is more effective in treating stage II prostate cancer.

PURPOSE: Randomized phase III trial to compare the effectiveness of two different doses of specialized radiation therapy in treating patients who have stage II prostate cancer.

OBJECTIVES:

• Compare the overall survival of patients with stage II adenocarcinoma of the prostate treated with high- vs standard-dose three-dimensional conformal or intensity-modulated radiotherapy.
• Compare the freedom from prostate-specific antigen failure, disease-specific survival, local progression, and distant metastases in patients treated with these regimens.
• Compare the probability of tumor control and normal tissue complications in patients treated with these regimens.
• Compare the incidence of grade 2 or greater genitourinary and gastrointestinal acute and late toxicity in patients treated with these regimens.
• Compare the quality of life, including sexual function, of patients treated with these regimens.
• Correlate histopathologic or tumor-specific cytogenetic or chromosomal markers with cancer control outcomes in patients treated with these regimens.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to Gleason score and prostate-specific antigen (PSA) level (Gleason score 2-6, PSA ≥10 mg/mL but < 20 ng/mL vs Gleason score 7, PSA < 15 ng/mL) and radiation modality (three-dimensional conformal radiotherapy [3D-CRT] vs intensity-modulated radiotherapy [IMRT]). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo standard-dose 3D-CRT or IMRT once daily, 5 days a week, for 7.8 weeks (39 treatment days).
• Arm II: Patients undergo high-dose 3D-CRT or IMRT once daily, 5 days a week, for 8.8 weeks (44 treatment days).

Quality of life (QOL) is assessed initially at baseline. After completion of radiotherapy, QOL is assessed every 3 months for 1 year and then every 6 months for 4 years.

Patients are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 1,520 patients (760 per treatment arm) will be accrued for this study within 5 years.

• Active Comparator: Patients undergo standard-dose three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) once daily, 5 days a week, for 7.8 weeks (39 treatment days).
• Experimental: Patients undergo high-dose 3D-CRT or IMRT once daily, 5 days a week, for 8.8 weeks (44 treatment days).

• Potrebko PS, McCurdy BM, Butler JB, El-Gubtan AS, Nugent Z. Optimal starting gantry angles using equiangular-spaced beams with intensity modulated radiation therapy for prostate cancer on RTOG 0126: A clinical study of 5 and 7 fields. Radiother Oncol. 2007 Sep 6; [Epub ahead of print]
• Cranmer-Sargison G. A treatment planning investigation into the dosimetric effects of systematic prostate patient rotational set-up errors. Med Dosim. 2008 Autumn;33(3):199-205.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate

  • Clinical stage T1b-T2b

• Meets one of the following criteria:

  • Gleason score 2-6 AND prostate-specific antigen (PSA) ≥ 10 ng/mL but < 20 ng/mL
  • Gleason score 7 AND PSA < 15 ng/mL
• No regional lymph node involvement
• No distant metastases

PATIENT CHARACTERISTICS:

Age:

• Any age

Performance status:

• Zubrod 0-1

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• No other invasive malignancy within the past 5 years except localized basal cell or squamous cell skin cancer
• No other major medical or psychiatric illness that would preclude study participation
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior cytotoxic chemotherapy
• No concurrent cytotoxic chemotherapy

Endocrine therapy:

• At least 3 months since prior finasteride

• No other prior hormonal therapy, including:

  • Luteinizing hormone-releasing hormone agonists (e.g., goserelin or leuprolide)
  • Antiandrogens (e.g., flutamide or bicalutamide)
  • Estrogens (e.g., diethylstilbestrol)
• No concurrent (neoadjuvant or adjuvant) hormonal therapy

Radiotherapy:

• No prior pelvic irradiation or prostatic brachytherapy

Surgery:

• No prior radical surgery (prostatectomy) or cryosurgery for prostate cancer
• No prior surgical castration (bilateral orchiectomy)

Other:

• At least 3 months since prior finasteride or PC SPES